Pollution test takes aim at stale ales

A TEST normally used to detect heavy metal pollution in water could soon be helping ensure the beer you buy is always fresh. By measuring concentrations of the chemicals responsible for the "cardboard" taste of stale beer, it will help to predict which batches are likely to go off before their time. So breweries will be able to ditch batches that could have a short shelf life.

As any home brewer knows, making beer can be a tricky process. Fermentation involves nurturing a warm reaction in which live yeast feasts on a malt liquor. But even under controlled conditions, the resulting brew can vary widely in taste. "Making beer is not like making a car, you don't always get the same product," says Aquiles Barros, an analytical chemist at the University of Porto in Portugal. Minute differences in the beer's composition can create a beer that lasts 5 months rather ...

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